Fewer than 20 percent of Americans support the war in Afghanistan, making the longest conflict in the nation's history the least supported war as well, a new CNN poll released Monday reveals.

According to the CNN/ORC survey of 1,035 adults nationwide, 82 percent said they oppose the conflict in Afghanistan, up from 46 percent five years ago. Only 17 percent of respondents in the survey taken Dec. 16-19 said they still support the war effort in Afghanistan.

"Those numbers show the war in Afghanistan with far less support than other conflicts," said Keating Holland, CNN Polling Director. "Opposition to the Iraq war never got higher than 69 percent in CNN polling while U.S. troops were in that country, and while the Vietnam War was in progress, no more than six in 10 ever told Gallup's interviewers that war was a mistake."

All U.S. troops are scheduled to be withdrawn from Afghanistan by December 2014, and over half of those polled would like to see them withdrawn sooner. About 25 percent said they believe that some troops should remain in the country after that deadline.

The poll found that only one-in-three respondents believe that the U.S. is actually winning the war there and 57 percent think it is going badly.

"Independents have a much gloomier view of the war in Afghanistan than Republicans or Democrats," Holland said. "That may be because a Republican president started the war and a Democratic president has continued it, so there may be some residual support among people who identify with either party."

The government of Afghanistan and the Obama administration are working to reach a bilateral security agreement, which would allow 10,000 troops to remain in the country after 2014. Currently, 47,000 U.S. troops remain in the country. A draft security arrangement was reached in November, but so far Afghan leader Hamid Karzai has refused to sign it.